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ASCI Turnpike Mining Resources SWSP Page 3 of 9 <br /> November 25, 2024 <br /> annual evaporation is estimated to be 39 inches per year. Net evaporation is defined as gross <br /> evaporation less the consumptive use of water by vegetation that naturally occurred at the <br /> site prior to construction of the pit. The historical consumptive use was assumed to be equal <br /> to the effective precipitation, which was estimated based on the data from the Longmont <br /> South NCWCD weather station (record 1994-2018). <br /> Table A - Summary of Evaporative Depletions <br /> Cells 2A Ft 213 Cell 3 Cell 4 Cells 5 and 6 Total <br /> Exposed Area 2.00 4.50 2.93 3.80 13.23 <br /> acres <br /> Unlagged Depletions 5.00 11.26 7.33 9.51 33.10 <br /> Total evaporative depletions are estimated at 33.10 acre-feet during this SWSP period, as <br /> shown on Table 2 (attached). <br /> Lagged Depletions <br /> The IDS AWAS stream depletion model was used to determine the lagged depletions from <br /> evaporation. There are no more lagged effects from past dewatering and operations. The <br /> aquifer characteristics used in the model are as shown in the following Table B using the <br /> alluvial aquifer boundary condition. <br /> Table B - IDS AWAS Parameters and Lagged Depletions <br /> Transmissivity Specific Yield W distance X distance to Lagged <br /> Cell (gpd/ft) M to boundary stream (ft) Depletions <br /> ft acre-feet <br /> 2A and 213 44,883 20 3,400 3,050 5.32 <br /> 3 44,883 20 3,400 650 11.16 <br /> 4 44,883 20 1,350 275 7.33 <br /> 5 Ft 6 44,883 20 1,350 600 9.51 <br /> Total - - - - 33.31 <br /> The total lagged depletions for 2025 are equal to 33.31 acre-feet (Table 3, attached). For <br /> purposes of this SWSP, the point of depletion for the gravel mining operation shall be on <br /> Boulder Creek where Boulder Creek crosses the north line of Section 31, Township 2 North, <br /> Range 68 West, 6t" P.M. <br />